Evolution by natural selection is a biological theory that explains the diversity of all life on Earth. Originally the theory of evolution was thought to have no say on the minds of conscious beings, but rather just an excellent explanation for how these beings came into existence. Scientists happily left it at that point and we relied on the philosophers and psychologists to explain the huge range of emotions, feelings and thoughts that human beings experienced. It was thought that at some point along the line of human evolution we were given some special quality, whether it evolved or was implanted supernaturally, that made us different to the animals. The standard opinion of the social sciences merely suggests that biology has given humans our five senses, hunger, fear and a capacity to learn (Pinker, 1997). So from this, the majority of people deduce that either this special quality, or learning through culture, gave us our intricate and complex minds, our intelligence and our ability to differentiate right from wrong. In recent years however two disciplines have begun to overlap. We now have evolutionary biologists taking an interest in human psychology and conversely psychologists and the social scientists seeking to understand evolution comprehensively. Thus ‘Evolutionary Psychology’ is born. A theory that seeks to rely on fundamental principles of evolution by natural selection to account for the nature of human minds and subsequently human behaviours (minds determine behaviours).
An understanding of evolution by natural selection is critical to understanding this concept. Charles Darwin observed that species tend to remain constant in numbers over time although they have the ability to reproduce exponentially. From this he inferred that there must be competition between organisms for resources and space. Another observation was that organisms tend to be rather well ‘designed’ to be successful in the environment they are present in. To explain this, Darwin postulated that those organisms with traits most well suited to their environment would be more likely to survive and reproduce, thus (given heredity) the offspring of these individuals would also have these traits and as a result these individuals would also have advantageous traits for surviving and reproducing and would pass them on to their offspring. And on and on the chain goes, individuals becoming more and more suited to their environments (Raven and Johnson, 1986).
We, as human beings, are just a part of this process. So why would it be odd to assume that our minds are a result of this process? Surely a sharp mind would have always provided an advantage in evolutionary terms. The basic claim of evolutionary psychology is that our minds are just as much a result of natural processes as our thumbs are. This argument starts with the assumption that it is the genes that are the basic unit of natural selection (Dawkins, 1976). Genes code for various traits of the mind and body. The logical step to make from here is to say that the genes that were most successful, over the evolutionary history, at coding for intelligent and complex brains (among other things) would go on to propagate more readily than those that didn’t code for such things. Thus the human mind became more and more suited to surviving and reproducing in its ancestral past.
It is important to point out that most evolutionary psychologists do not try and claim that every single aspect of human thought and behaviour is directly in line with Darwinian Theory. It may be true that other animals devote every waking moment to simply survival and reproduction, but it is worth noting that humans do many things that would appear to contradict Darwinian Theory. This is explained well by (Pinker, 1997), who states that natural selection has taken place over thousands of generations and most of them (99%) were in an environment vastly different to the one that humans are in today. The majority of time that natural selection has been acting on human minds has occurred in hunter/gatherer type environments. A far more brutal and desperate time when concepts such as love, sharing and trust were in their infancy. It is not surprising that minds designed to thrive in those times do not always make complete sense in these times where many of the pressures of the past are just a shadow of their former selves. One cannot help but think of the countless amount of time squandered trying to beat mental illness and find meaning in a seemingly meaningless world. Depression rates are higher than ever before, because our brains have been ‘designed’ to survive and reproduce. Clearly in our ancestral past, the capacity to remember everything bad (that may threaten survival) would have conveyed some survival success. Evolution has created the perfect worrier. However, a typical human in modern times is not anywhere near as worried that his neighbour will break into his house, steal his possessions and attempt to impregnate his wife. The lives of present day humans have other far more manufactured pressures to deal with. These pressures, such as paying bills, maintaining a job and social status have lead to many inventions which are in direct contradiction to Darwinian Theory. These constructions create perfect misery for some and the opportunity to be ‘top dog’ for others. Interestingly, the very notion of sex without the goal of reproducing would surely seem absurd to our ancestors, if they could even comprehend it. Contraceptives reflect the interchange of Darwinian programming and modern day pressures. One can’t simply just go about conceiving limitless numbers of babies without having a great deal of responsibility to care for them. Society has made this sort of behaviour very expensive. Pinker sums it up nicely “Since the modern mind is adapted to the Stone Age, not the computer age, there is no need to strain for the adaptive explanations for everything we do” (Pinker, 1997).
Now we turn our attention to the things that evolutionary psychology can explain. One of the best examples that we can draw from evolutionary psychology is that of phobias. There are many things that human beings are afraid of that seem irrational in the light of the modern world in which we live. For instance one of the most common phobias is snakes and spiders. Now this was once probably quite a rational fear given the likely ways in which humans used to live. There were certainly no fly proof screens attached to all windows and doors of houses, if there even were houses. Snakes and spiders could have been in regular contact with people at certain times in history and given the almost complete lack of proper medical treatment, a bite from them may have been somewhat closer to a death sentence than it is today. As a result the trait ‘being afraid of snakes and spiders’ would have had some survival benefits. Picture the dim-witted cave man rushing up to a snake and trying to pick it up. The chances are that these genes wouldn’t be passed on. So evolution by natural selection has programmed phobias into human beings, obviously they effect different people in varying degrees.
Another simple example of evolutionary psychology is that of hunger and food cravings. It is generally accepted that in the early days of human history, which maybe anywhere between 100,000 and 250,000 years ago, high quality food was in scarce supply. Individuals who had a genetic predisposition to crave these high quality foods would be more likely to go and seek them out. The consumption of these high quality foods would have lead to an increase in health and thus fecundity. Conversely the individuals who lacked that desire to seek out these high quality foods would have been likely to just go for whatever happened to be close by, which would probably have been, on average, lower quality. Our present-day sugar cravings can most likely be attributed to the once rare and valuable status of sugar. Loading up when one could was wise, because there was no guarantee when the next opportunity would arise. However nowadays sugar has been added to almost everything in rather generous proportions, as evidenced by the equally generous proportion of many waistlines. We as a species have become fat and lazy, when compared with our ancestors, who would (in some cases, literally) make a meal of us.
The punishment and justice system can be explained by looking into our evolutionary past. Suppose (in cave man days) I wanted to have the lice removed from my hair, this is a task I would need someone else to do, before the days of shampoo or running water. I offer to return the favour in exchange, now I have to be rather selective about my business partner. Say I was willing to help just anyone, there would of course be some who would not hold up their end of the bargain. I would be greatly benefitted if I could learn to distinguish the honest members of society from the dishonest one’s. I will be likely to strengthen my links with the honest members and begin to trust them. The dishonest one’s will begin to be shunned by others and even ostracized. Notions of right and wrong could have developed from this. Those who refused to do right may have faced some sort of retribution or punishment for their wrongdoings (Singer, 2005).
A particularly fascinating argument in favour of certain innate tendencies is the study of identical twins. Many psychologists have strongly supported the view that human beings are born as relative blank slates with no hard wired tendencies or personality traits. However when studying the psychology of identical twins who were separated from one another and raised in separate families, it becomes quite clear that this is not the case. These twins will more often than not share many traits such as IQ, neuroticism and introversion. Mathematical and language abilities are often similar. Even opinions on philosophical and political opinions can be held in common. They share similar interests in careers, tend toward certain religious beliefs and may be absorbed by the same vices. Behavioural quirks like entering the water backwards, obsessively counting everything and flushing the toilet before and after use have also been found in common (Pinker, 1997). These tendencies just don’t make sense in the light of blank slate theory, there simply must be some pre-programmed code for how to live one’s life.
One of the major challenges of evolutionary psychology is that it is very hard to ever prove that certain mental processes and behaviours are evolved from a specific ancestral selective pressure. It is a process of engineering in reverse which is complex and difficult to explain. The premise of evolutionary psychology seems to be simultaneously unprovable and inescapable. Nothing else would make more sense, yet the difficulty associated with finding empirical evidence to support the claim leaves one questioning it. It seems that the discipline is somewhat more of a philosophical claim than a scientific claim as it rests on the validity of sound and logical argument rather than surviving rigorous scientific testing. This problem certainly should not delegitimize Evolutionary Psychology, but rather force it to look for new approaches to solving the mysteries of human behaviour. The animal kingdom can be looked at, if we can find similarities between the behaviour of chimpanzees and human beings, then we can say with more confidence that our minds are an evolved faculty. Modern chimpanzees are the closest living relatives that we have, in fact we share 99% of the same DNA as them. So it is not unreasonable to assume that modern man once resembled something rather like a chimpanzee. It is well established that humans and chimps have quite a lot in common both mentally and physically: social grouping, affection, communication, ability to walk upright and use of tools. This a brief and simple summary of some of the many similarities.
Now the task for the Evolutionary Psychologist is to set out why these traits have been selected for. What is the functional mechanism behind a mind that does these things? Social grouping and affection are most likely a result of reciprocal altruism. Many of the apparently altruistic actions undertaken by animals can often be traced back to a point where the action although seeming altruistic is actually still ‘selfish’ in the sense that it is benefitting the individual who is doing the act (the genes of the individual) (Dawkins, 1976). This premise, if true, leads quite logically to the creation of social groups whereby multiple individuals help one another to do various tasks. It may seem like these acts are altruistic or for the good of the species/group but this is not the case. These acts are very much for the sole benefit and survival of the genes of each individual. The many forms of society that humans have created today almost certainly owe their origins to this reciprocally altruistic behaviour in the early days of our ancestors existence.
A common argument against is to claim that a Darwinian world is not the type of world that humans live in, nor is it the type of world that any rational human would want to live in. This is a true statement however to use it as an argument against evolutionary psychology, is to misunderstand what evolutionary psychology is saying. It is not claiming that we live in a survival of the fittest kind of world. It is simply stating that our minds have been shaped by ancestral selective pressures. It is quite clear that humanity has manufactured a world in which many of the pressures of our ancestral past have been removed.
The only major criteria for being a good explanation, that Evolutionary Psychology falls short on, is that of falsifiability and it seems that this is the major area of criticism of the theory. Given the reverse nature of the theory it is true that definitive answers are difficult to reach. The recent rapid increases in technology and expanding knowledge of neuropsychology is enabling scientists to accurately map various firings of neurons and the subsequent behaviours and thoughts. This is a step towards achieving empirical evidence and thus enabling the theory to be falsifiable. One of the significant findings in recent times is that decisions are made in the mind before humans are consciously aware of them. This has been done through the use of functional magnetic resonance imaging (FMRI), and it found that decisions are made by the brain up to a full 7-10 seconds before the person was consciously aware that they were making the decision (Haynes, 2011). These results, among others, support the claim that free will is an illusion. Meaning that people are not actually in control of every decision that they make, rather the brain makes the decision and then the conscious awareness of the person catches up and goes ahead believing that it is making the decision (Harris, 2010). This has something of the elephant and the rider proposed by Haidt. From this, a logical conclusion to draw is that there is some innate element to the human mind, controlling how we think, feel and behave.
Evolutionary psychology provides the only working explanation for the nature of human minds. At its core, it rests solely on the back of the most powerful and comprehensive scientific theory, that proposed by Darwin. The theory requires no postulating of other entities and thus fares very well with Ockham’s razor. Other theories such as culture and learning, although convincing at first, simply fall back to an evolutionary basis once examined. Our ability to learn comes from our innate tendencies which have been programmed by hundreds of thousands of years of evolution by natural selection. It is this same process that created the culture that we now live in. It may be true that culture plays a role in shaping minds, but the origins of culture are surely evolutionary processes designed to make things easier for our survival machines to propagate those selfish genes.
Dawkins, R. (1976). The Selfish Gene. London: Oxford University Press, pp.1-48.
Dennett, D. (1995). Darwin’s Dangerous Idea: Evolution and the Meanings of Life. New York: Simon & Schuster, pp.187-229.
Harris, S. (2010). Free Will. New York: Free Press, pp.1-5.
Haynes, J. (2011). Decoding and predicting intentions. Annals of the New York Academy of Sciences, 1224(1), pp.9-21.
Pinker, S. (1997). How the Mind Works. New York: W W Norton, pp.1-58.
Raven, P. and Johnson, G. (1986). Biology. St. Louis: Times Mirror/Mosby College Publishing, pp.367-374.
Singer, P. (2005). Ethics and Intuitions. J Ethics, 9(3-4), pp.331-352.